Method of treating steam boilers



May 4, 1943.

F. W. MILLER METHOD OF TREATING STEAM BOILERS 2 Sheets-Sheet 1 Filed July 3-, 1941 INVENTOR.

BY flank I May 4, 1943. F w, MlLLER 2,318,247

METHOD OF TREATING STEAM BOILERS Filed July 3, 1941 2 Sheets-Sheet 2 INVENTOR.

Y Fan/a Q? Patented May 4, 1943 METHOD OF TREATING STEAM BOILERS Frank W. Miller, Chicago, 111., assignor to Franclare Company, Chicago, 111., a corporation of Illinois Application July 3, 1941, Serial No. 400,932

2 Claims.

This invention relates to the treatment of steam boilers for the purpose of relieving them of the scale and sludge which accumulates therein during their operation, for refilling the boilers with fresh water after being cleaned, and for simultaneously establishing therein a working steam pressure.

The method most commonly employed in cleaning boilers is to blow oiT the steam and water, drain out any remaining water, and then wash the boiler by delivering jets of wash-out water at various angles and at various locations into the boiler, in an endeavor to loosen and knock off the accumulated scale and force the sludge and other solid material toward the drain opening through which it is discharged.

The opening up of the boiler to atmosphere after the steam and water have been discharged results in a rapid drying and caking of the objectionable solid matter which it is desirable to remove from the boiler. This drying and caking is increased by the heat existent in the crown sheet and tubes, with the result that the encrusted solid matter adheres with such tenaciousness to the boiler surfaces that its removal by the jets of washing water is rendered impossible;

One of the purposes of my present invention is to preclude this drying and caking of the solid matter upon the boilersurfaces and to remove the matter from the surfaces while in a soft and.

uncaked condition. With this end in view, my invention contemplates the internal washing of the boiler with jets of high pressure water while some water and substantial steam pressure remain in the boiler, so that the atmosphere is excluded from the boiler and all the surfaces remain in a, wet condition, which is most conducive to the removal of the sludge and solid matter therefrom.

In ordinary boiler practice, the boiler is cooled down during the washing operation to such a point that when refilled with hot water the lower portions of the boiler contacted by the water are heated, while the upper portions remain relatively cool, thereby causing unequal expansion of different areas of the boiler shell, with the result that the boiler is subjected to injurious stresses and strains.

Another purpose of my present invention is to eliminate the imposition of such inj urious stresses and strains upon the boiler by heating it up evenly throughout, so that the various areas are expanded uniformly and simultaneously- This purpose is accomplished by supplying the .boiler with only a relatively small quantity of'water so as to merely cover the blow-oh cock openings and then admitting steam into the boiler below 'the water level, which steam will disperse and-enter all portions of the boiler so .as to heat them equally. The admission of steam is continued until a substantial pressure, preferably in the neighborhood of pounds, is attained in the boiler, at which time all portions of the shell will have been simultaneously and uniformly heated and expanded without producing injurious strains and stresses incidental to unequally heating the boiler. V

In ordinary practice, when the boiler has been refilled to the desired water line with hot water, the fires are then lighted in the firebox and'a long period of time is required before suiiicient steam for self-propulsive purposes of the locomotive can be produced. In an efiort to reduce the idle period of the locomotive, the practice in some roundhouses is followed of introducing steam into the boiler after the working water level has been attained, so as to produce a selfpropulsive steam pressure in the boiler. Con densation of part of the steam thus introduced raises the water level in the boiler so that it is usually necessary to blow oif and waste a portion of the hot Water in order to keep the water'level down to the requisite height. The steam pressure attained in the boiler by this practice is temporary only, and falls ,very rapidly when 7 attempted to be used for self-propulsive purposes, because the water in the boiler is not at steaming temperature. The result has been that locomotives thus treated are capable of proceeding only a very limited distance under their own'power, and often fail of self-propulsion after leaving the roundhouse, before they reach the yards.

In accordance with my invention, after the boiler has been heated and expanded, water unbe so utilized to a substantial degree, because the water is already at steaming temperature and charged with latent heat and ready toiflash into steam upon a slight reduction in. the steam pressure. The locomotive may, therefora be propelled from the roundhouse under its own steam to a convenient location where it may be fired for service.

To facilitate an understanding of my invention, I have illustrated on the accompanying drawings as an exemplification one form of apparatus by which my improved method may be carried out.

Referring to the drawings,

Fig. 1 is a schematic View of an apparatus by which my invention may be practiced;

Fig. 2 is a View showing the arrangement employed at one of the drops;

Fig. 3 is a longitudinal sectional view through the water superheater shown in Fig. 2; and

Fig. 4 is a fragmentary detail of one of the adjustable nozzles.

Referring to the drawings more in detail, reference character 5 indicates generally a locomotive stationed at a pit in a roundhouse between a two adjacent drops. The apparatus at each drop in the roundhouse is preferably of the character disclosed in my Patent No. 2,260,857. As shown in Fig. 2, a suitable bracket or other support 6 carries the blow-off line I, the refill water line 8, the live steam line 9 connected to be supplied with steam from the powerhouse boilers and, in many instances, a washout water line, which in the present instance is not shown.

For the purpose of superheating the refill water to be delivered to a boiler being treated, a water superheater or heat booster of the character illustrated in Fig. 3 is preferably employed. Such a booster comprises a cylindrical casing H provided intermediate its ends with a Venturi tube 12 disposed in alignment with a water delivery nozzle l3 having a flange [4 clamped to the upper end of the casing II by supporting bolts 15 and IS. The inlet end of the nozzle is connected by a pipe IT with the refill water line 8, and in the pipe I] is interposed a check valve l8 and a shut-off valve IS. The superheater may be mounted at any desirable height above the fioor, but when mounted sufficiently high to be out of the way of workmen around the pits, as illustrated in Fig. 2, the valve I9 is equipped with an operating lever 2| adapted to be operated through the intermediary of pull chains 22 and A pipe 24 is connected at one end with the casing H above the-venturi tube 12, so asto communicate with the valve 25 surrounding the nozzle i3 and receives its steam supply from the steam line 9. The pipe 24 is preferably squipped with a shut-off valve 23 and with a regulating valve 21 by which the amount of steam delivered to the superheater may be regulated. This valve also, when located at an inaccessible height, is equipped with operating pull chains 28.

A branch 29 leading from the casing l I below the venturi is connected by a pipe 3| with the blow-off line 1, and this pipe is also equipped with a check valve 32 and a. shut-off valve 33 adapted to be operated by lever-34 to which are connected operating pull chains 35 and 36. r v

A flexible conduit in the form of a hose or a pipe 31 provided with flexible joints 38 is equipped at its free end with a coupling wrench 39 by which the conduit may be connected with the blow-off cock or the washout plugs of a locomotive boiler.

Referring to the schematic layout of Figure 1, it will be apparent that the steam line 9, the blow-off line 1 and the refill line 8 may be connected with the locomotive boiler through the common conduit 31 at will. The various -connections are established as desired through manipulation of the valves 33, I9 and 21. From this figure it will be apparent that the blow-oil line is adapted to deliver into a steam separator 4| by which the blow-off steam and water are separated. This separator is preferably of the centrifugal type from which the blow-off water is discharged through a pipe line 42 either to a waste conduit or preferably to a storage tank where the water is stored for boiler washout and other useful purposes. The sludge accumulated in the separator may be discharged to waste at suitable intervals through a discharge pipe 43 controlled by a valve 44. The steam from the separator is conducted through a line 45 to a condenser 46, preferably of the open type through which water is circulated to condense the steam. This condensing. water is taken from the refill storage tank 41 and delivered by a pump 43 through the line 49 to the condenser, from which it is returned through the line 5| into the refill storage tank. Additional water is supplied to the tank as required through a fresh water supply pipe 52. The details, not shown, of the condensing system may be of the general type disclosed in my prior Patent No. 2,135,407, issued November l, 1938. Refill water is delivered to the refill line B from the storage tank 4'! by means of a pump 53 in the usual manner.

In practicing my improved method of treating boilers, the system above described is utilized in the following manner:

A locomotive to be treated is positioned on a pit between two drops and the lefthand drop, for instance, viewing Fig. 1 is connected thereto through the conduit 31 which is attached to the blow-01f cock of the locomotive. Valves l9 and 21 are closed and valve 33 is opened, thereby permitting the boiler contents to be blown ofi through the blow-ofi line I, the steam and water being separated by the separator M, the blow-off water being thrown away or conserved, as preferred, and the steam being condensed and stored in the refill storage tank.

Instead of blowing off all of the water and steam from the boiler, then opening up the boiler and washing it out as has heretofore been customary, my invention contemplates interrupting the blowing off operation when about two-thirds of the water has been blown off and about pounds steam pressure remains in the boiler. This interruption is effected by closing the valve 33. Thereupon the conduit 31 is connected with the boiler for washing purposes. The connection is made successively to the various washout plugs, some of which are customarily equipped with nozzles disposed inside the boiler and adapted to be turned to various positions so as to discharge a cleaning jet of water in various directions within the boiler. A typical nozzle for this purpose is indicated by reference character 53 in Fig. 4. This nozzle is rotatably mounted in the plug 54 and connected by a swivel joint 55 with the conduit 31. Rotation of the nozzle to vary the direction of discharge therefrom is effected by means of the handle 56. When the connection to a washout plug has been established, at the righthand side of the boiler, for instance, valve 33 is left closed, valve [9 is opened, and valve 21 is also opened or partially opened so as to heat the delivered water to 250 or more. The water in the refill line is delivered by a suitable pump atto 200 pounds pressure,

7 which is materially higher than the pressure existent in the boiler. This water has been previously heated by waste products from the boiler washing system and exhaust steam from' the power boilers to a temperature approaching 200, and, as has been previously stated, is then further heated by steam from the line I delivered through valve 21 until the temperature of the high pressure water when delivered to the boiler is only slightly below the temperature of the boiler under the pressure existent therein. Because of this slightly lower temperature, the delivered water does not flash into steam but is delivered as a solid high pressure jet against various interior surfaces of the boiler so as to remove the sludge, scale and other solid matter which has accumulated on these surfaces. Since the boiler still contains water and steam and has not been opened to atmosphere as has heretofore been customary, no opportunity has been afforded for the accumulated solid matter to become caked upon the boiler surfaces, consequently, it is in a somewhat soft and non-adherent condition which is conducive to its removal from the boiler surfaces. The maintenance of the boiler in hot condition and the delivery of hot washing water also contribute toward the freeing of the solid matter from the boiler surfaces, so that greatly superior results are attained than are possible with the usual practice where the boiler is permitted to cool down and is washed with relatively cool water.

After the washing of the interior of the boiler with high pressure high temperature water has been partially completed, the blowing oiT operation is again resumed by opening the lefthand valve 33 (viewing Fig. 1) so that the solid matter which has been washed off of the boiler surfaces will be blown out of the boiler along with the blow-off water and deposited in the separator 4|,

\ from which it may be discharged as previously explained. The washing of the boiler with hot high pressure water may be continued during the final blowing oif operation, with the result that when the boiler has been completely emptied it is substantially free from the accumulated solid matter, and, unless repair work is required, it may be immediately refilled without being opened up to atmosphere or unduly cooled down. Even when washed in accordance with my method, without being opened to atmosphere, the temperature of the boiler is materially reduced below the normal working temperature, so that some contraction of the boiler has occurred. The amount of contraction, however, is relatively small as compared with that encountered in the ordinary practice of washing boilers, and, since the boiler has remained under steam pressure during practically the entire washing operation, such contraction as does occur is uniform and does not impose injurious strains and stresses upon the various boiler parts.

If repair work is required or for other reasons it becomes necessary to open up the boiler after it is washed, the cooling of the boiler will, of course, proceed to a much greater degree. In either event, whether refilled immediately after being washed out and without being opened up or if opened and permitted to cool, the refilling in accordance with my method results in a uniform heating up of the boiler throughout its entire area and a consequent uniform expansion, which obviates the stresses and strains ordinarily imposed upon a boiler with injurious results when refilled directly with hot water, as has heretofore been customary.

In accordance with my method, whether the boiler be cold or relatively hot, the refilling is performed in the following manner:

One or both of the conduits 31 is connected to a blow-01f cock or cocks and by the opening of the valves I9 and 21 hot water at a temperature preferably from 160 to 180 is admitted to the boiler until the blow-ofi cocks are covered. Only a relatively small amount of water is required for this purpose, depending, of course, upon the size of the boiler, but for an average boiler 200 gallons will probably suffice. When the blow-off cocks are covered, the valve I9 is closed and steam only from the steam line 9 is permitted to enter the boiler. This steam delivered below the water level in the boiler passes upwardly through the water into the space above and, as the volume of admitted steam increases, it will fiow into and fill all of the boiler spaces, so that they are all subjected to the same gradually rising temperature and, consequently, all portions of the boiler will expand uniformly without producing injurious stresses and strains which are inevitably occasioned by unequal heating of the boiler. This heating of the boiler is continued until a steam pressure approaching to pounds has been established in the boiler, at which time the boiler will have been uniformly and very largely expanded.

After the attainment of such a pressure, the water valve I9 is opened and refill water under a pressure and temperature higher than the pressure and temperature existent in the boiler is delivered to the boiler. A portion of this high temperature high pressure water flashes into steam upon its release into the boiler, with the result that as the water level rises the steam pressure also rises and the water is retained at steaming temperature charged with latent heat and ready to flash into steam upon any pressure reduction.

The filling of the boiler with this high temperature high pressure water is continued until the desired water level is attained therein, at which time the boiler will be under a pressure suflicient for self-propulsive purposes of the locomotive, and, due to the latent heat with which the water is charged, the steam used within reasonable limits for self-propulsive purposes will be immediately replaced by steam flashing from the high temperature water. The conditions thus attained in the boiler enable the locomotive to move under its own power from the roundhouse to a station where it may be fired and made ready for road work.

It is believed that procedure in accordance with my method will be understood from the foregoing, and that the advantages resulting from the practice of this method will be appreciated, all without further description. Variations in the method hereinabove described as illustrative and wide modification in the apparatus employed in practicing the method may obviously be resorted to within the scope of the invention as defined in the following claims.

I claim:

1. The method of treating boilers which comprises delivering water to an empty boiler until a water level slightly above the level of the blowoff cocks has been established, discontinuing said water delivery, delivering steam only into the boiler below said established water level until a substantial steam pressure has-been attained in the boiler, thereby uniformly heating and expanding the boiler, and then refilling the boiler to the desired water level by delivering superheated water thereto at a temperature and pres sure greater. than the temperature and pressure existent in the boiler to thereby produce a selfpropulsive steam pressure in the boiler simultaneously with the attainment of the desired water level.

2. The method of refilling boilers without the production of injurious stresses and strains incident to unequal expansion of the parts thereof, which consists in introducing hot water into the boiler until a water level slightly above the level of the blow-ofi cocks has been established, dis- 10 the boiler.

continuing the introduction of such Water, delivering steam into the boiler below said established water level until a substantial steam pressure has been established therein to thereby uniformly heat and expand the boiler, discontinuing such delivery of steam, and then delivering superheated water into the boiler at a temperature and pressure in excess of that existent in the boiler until a working water level has been produced in FRANK W. MILLER. 

